Unable to activate plugin

Hey,

i’m not able to activate this plugin, because of this error:

Fatal error: Cannot redeclare add_ajax_library() (previously declared in /var/www/wordpress/wp-content/themes/pluto/functions.php:272) in /var/www/wordpress/wp-content/plugins/all-in-one-schemaorg-rich-snippets/functions.php on line 787

can you help me?

kind regards,

https://wordpress.org/plugins/all-in-one-schemaorg-rich-snippets/